1. Field of the Invention
The present invention relates to an antenna device.
2. Description of the Related Art
A wideband array antenna is known that has an inverted-F antenna as a feed element and a non-feed element having a prescribed length erected on a ground plate. In such a wideband array antenna, a part of the non-feed element is disposed at an upper side at a prescribed distance from the feed element, and the respective element lengths of the non-feed element and the feed element are arranged to be different from each other (See e.g., Japanese Laid-Open Patent Publication No. 2001-160710).
It has been difficult to miniaturize antenna devices such as the wideband array antenna described above because of the arrangement of the inverted-F antenna and the non-feed element on the ground plate.